The present invention relates to a motor vehicle fitted with an electric motor and comprising an electronic power circuit cooled by a cooling circuit in which a coolant fluid circulates. This cooling circuit comprises a radiator for heating the passenger compartment. This radiator for heating the passenger compartment can transfer the calories carried by the coolant fluid of the cooling circuit to the air of the passenger compartment of the vehicle.
Document FR 2 757 456 describes a motor vehicle which comprises an electric motor and an electronic power circuit cooled by a cooling circuit in which a coolant fluid circulates. This cooling circuit comprises a heating radiator that can transfer the calories of the hot coolant fluid to the air of the passenger compartment of the vehicle. In order to boost the heating produced only by the coolant fluid of the cooling circuit, the aforementioned document proposes to use a two-layer heating radiator. In one of these layers, the coolant fluid of the cooling circuit circulates, while the other layer forms part of a second circuit in which a second coolant fluid circulates which can be reheated by an electric resistance connected to the battery of the vehicle.
Although the heating of the passenger compartment of the vehicle is improved by the device recommended by the aforementioned document, heating of the vehicle on starting remains problematic. Specifically, on starting, the fluid of the cooling circuit is cold and the heating must therefore use only the second layer in which the coolant fluid is heated by a resistance which draws its electric energy from the battery of the vehicle. However, in cold weather, the chemical reaction that takes place in the battery is greatly slowed and the battery cannot always start the vehicle and therefore supply energy to the aforementioned heating resistance.
The lack of heating of the passenger compartment is not only a problem of comfort. It may be dangerous because of the misting covering the windows of the passenger compartment which greatly hampers driving and even prevents it totally.